For Those On Antibiotics

10 capsules |10 days' supply

Dr Sasivimol Ahmed PhD, PG Dip (Personalised Nutrition), BSc (Food Science)
A live cultures supplement that I recommend regularly for those taking or who have recently finished antibiotics.
Dr Sasivimol Ahmed
Dr Sasivimol Ahmed PhD, PG Dip (Personalised Nutrition), BSc (Food Science)

Who is it for?

For Those On Antibiotics is for anyone looking to buy a high-quality friendly bacteria supplement developed and proven especially to be taken alongside a course of antibiotics.

FREE UK delivery on orders over £40.

UK express - Monday to Friday delivery.

See our Delivery & Returns for more information.

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  • Vegan


  • No dairy

    No dairy

  • Gluten free

    Gluten free

  • Yeast free

    Yeast free

  • No added sugar

    No added sugar

  • Artificial colour free

    Artificial colour free

Key benefits

Friendly bacteria for antibiotics

Best for anyone looking for a natural friendly bacteria supplement to take at the same time as antibiotics.

  • Suitable to take with antibiotics Extensively researched and shown to be safe to take alongside a variety of antibiotics
  • Scientifically proven to reach the gut alive Strains survive, even when taken at the same time as antibiotics
  • Highly researched friendly bacteria Contains 3 strains which have been collectively researched in over 25 scientific studies specific to antibiotic use
  • Easy to take on a daily basis Designed to be taken once daily throughout a course of antibiotics. Can also be taken for longer periods alongside long-term antibiotics
  • A more natural option This vegan and gluten free supplement has no added sweeteners or flavourings
  • From the UK's most recommended brand Optibac is the brand of friendly bacteria supplements most recommended by UK consumers

Optibac Probiotics strains

  • Lactobacillus rhamnosus Rosell-11
  • Bifidobacterium lactis Lafti B94
  • Lactobacillus acidophilus/helveticus Rosell-52
See full ingredients list

General digestive


Complements gut bacteria

Customer Reviews

Customer reviews have been collected on our website or independently through Trustpilot where no moderation is possible. Reviews are not endorsed by us and should not be regarded as medical or health advice. For supplement advice, you can speak to one of our qualified experts. The top 3 reviews have been selected from our website, please click view all to explore more customer feedback.

Help & advice

Our team of qualified experts are available for free personalised supplement advice. If you're not sure where to start or your needs have recently changed, please get in touch.

Louise Mason
Louise Mason BA(Hons) DipCNM Nutritional Therapist, DipCNM Naturopath, mANP

Why choose us?

We are the UK's most trusted & recommended brand of friendly bacteria supplements as determined in an independent survey of 1000 people 

We use the most researched strains of friendly bacteria in the world with each supplement designed to target individual needs and life stages.

  • How to use

  • Ingredients

  • Leave a review

  • Delivery & returns

  • How to use

    Recommended use

    Food supplement suitable for adults and children, from 4 years onwards, with the following recommendations:

    • Take 1 capsule daily with food, preferably with breakfast, every day during your antibiotic course and for a few days afterwards or until the pack has been completed.
    • Can be taken at the same time as antibiotics - strains in this product have been clinically trialled alongside antibiotics and found to reach the gut alive.
    • Drink plenty of water with your course of live cultures.
    • For anyone unable to swallow capsules, open and mix contents of the capsule with a cool meal or beverage.

    Storage instructions

    • Store in a cool, dry place below 25°C and out of direct sunlight.


    Live cultures are not recommended for those with serious medical conditions e.g. those who are severely immunosuppressed, have pancreatitis, are in the ICU, have melaena, have a central venous catheter, infants with short bowel syndrome, or patients with open wounds following major surgery; unless under a doctor's care. Keep out of reach of children.

    Gut health supplements are not intended to prevent, treat or diagnose any medical conditions. If taking probiotic supplements for gut health, note that these should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. If you are taking any medications or have a serious medical condition, consult a doctor before use. Optibac supplements will not cause dependency and may be used on an ongoing basis.

  • Ingredients


    Stabiliser: potato starch; vegetarian capsule: hydroxypropyl methylcellulose; Live cultures: Lactobacillus rhamnosus Rosell-11, Bifidobacterium lactis Lafti B94, Lactobacillus acidophilus/helveticus Rosell-52; anti-caking agent: vegetable magnesium stearate; antioxidant: ascorbic acid

    Each capsule guarantees 4.5 billion live cultures.


    • Vegetarian
    • Vegan
    • No dairy
    • Gluten free
    • Yeast free
    • Suitable during pregnancy
    • Suitable during breastfeeding
    • GMO free
    • Free from artificial flavourings, colourings and preservatives
    • No chemicals or parabens
    • Sugar free

    Following the taxonomic updates advised by a global team of scientists and published in April 2020, a reclassification has been proposed for the L. rhamnosus species. The L. rhamnosus strain in For Those On Antibiotics may therefore now also be known as Lacticaseibacillus rhamnosus Rosell-11.

    Format Capsule
    No. Live Cultures 4.5 billion
    Recommended Use 1 capsule daily
    Age Range Adult
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  • Delivery & returns

    UK Delivery

    Free UK Delivery over £40 
    Free standard UK delivery is automatically applied at the checkout when you spend £40.

    Standard 2nd class: £2.50
    Allow 4-10 working days (Monday - Friday) for delivery 

    1st class: £3.95
    Allow 1-3 working days (Monday - Friday) for delivery 

    Express Next Day, order before 2pm (Tracked): £6.95 
    Allow 1-2 working day delivery to most of the UK*. Orders placed on Friday will be delivered on Monday (next working day). Requires signature.

    Shipments will be dispatched via DHL or FedEx, the service will be selected depending on the delivery location.

    *Express delivery may exclude the Channel Islands, Herm Island, Isle of Man, Isle of Wight, Northern Irish postcodes BT18 & upwards, Sark, Scottish borders and offshore and a small number of remote mainland destinations as determined by our delivery courier. 

    Good to know

    • We'll send you an email to confirm once your parcel has been dispatched.
    • For delivery queries, please call us on +44 (0)1264 339 770 or email
    • Orders placed before 2pm are typically dispatched on the same working day.
    • Delivery within the UK and Northern Ireland has a fixed price, regardless of the size and weight of your order. 
    • Delivery times are estimates and not guaranteed unless otherwise stated.

    International Delivery

    We offer an excellent worldwide delivery service. For more details, please take a look at our delivery FAQ.


    If you have changed your mind, you can return goods, at your cost, unopened within 14 days for refund or exchange, this does not affect your statutory rights.

Customer Questions

All questions answered by probiotic experts Dr Kate Stephens PhD (Food and Microbial Sciences) BSc(Hons) Medical Biology and Helen Morton BSc (Hons) DipION Nutritional Therapist

Yes! Taking live cultures with antibiotics is highly recommended.  However, it’s important to select supplements such as Optibac Probiotics For Those On Antibiotics, which contains strains extensively researched1,2 alongside antibiotic medication and shown to reach the gut alive.

Read references

Antibiotic medication can harm most delicate live cultures. Strains such as Lactobacillus acidophilus/helveticus Rosell-52, Lactobacillus rhamnosus Rosell-11 and Bifidobacterium lactis Lafti B94 have been have been specifically and extensively researched1,2 alongside a variety of antibiotic medication, proven to reach the gut alive, even when taken at the exact same time as short or long courses of antibiotic medication1,2,3. These strains can be found in Optibac Probiotics For Those On Antibiotics.

Read references

No. You can still take Optibac For Those On Antibiotics supplement with breakfast as recommended, regardless of when you take your antibiotics, because the strains are proven to be hardy against the effects of antibiotic treatment1. Other live cultures supplements, including Every Day EXTRA, need to be taken at least two hours away from the medication.

Read references

Live cultures are best taken with food, ideally breakfast, when stomach acidity is closer to neutral. It’s recommended to take 1 capsule of For Those On Antibiotics daily with breakfast - there is no need to take this probiotic at a different time of the day from the antibiotic. Ideally, start taking this supplement at the beginning of the course of antibiotics, but if that's not possible, rest assured these live cultures will still have a good chance of reducing any unwanted side effects. If you are taking Every Day EXTRA instead, we recommend that it be taken at a different time of day to the antibiotic medication, at least 1-2 hours apart, as it contains delicate bacteria which could be destroyed by the antibiotics.

Read references

Unlike the live culture strains in For Those On Antibiotics, the strains in Every Day EXTRA have not been extensively tested alongside antibiotic medication. Therefore, Every Day EXTRA is most suitable when taken after finishing a course of antibiotics, as it contains strains including Lactobacillus acidophilus NCFM® and Bifidobacterium lactis Bi-07®, which have been scientifically trialled for use after a course of antibiotics1.

Read references

Children from the age of four onwards can take Optibac Probiotics For Those On Antibiotics. The strains in this supplement have not been tested on infants and babies so we cannot recommend that under fours take it. Younger children who need to take antibiotics can be given our Babies & Children supplement, which is suitable for all ages from birth onwards. This supplement contains the renowned Lactobacillus rhamnosus GG strain which has been widely researched in children taking antibiotics1,2. For children of all ages, once their course of antibiotics has been completed we recommend they take one of our children's products for at least a couple of months to complement the gut microbiome.

Read references

It is highly recommended to continue taking live cultures for at least a month following a course of antibiotic medication. You can continue to take For Those On Antibiotics if this is easier, but another popular option is to swap to our Every Day EXTRA. This supplement contains strains including Lactobacillus acidophilus NCFM® and Bifidobacterium lactis Bi-07®, which have been scientifically trialled for use after a course of antibiotics1. This powerful supplement is just what your digestive system needs to complement and harmonise the gut microbiome after antibiotics. Many people find that their gut needs a bit more TLC after finishing a course of antibiotics, so they prefer to take a higher strength supplement like Every Day MAX for a month or two before before resuming their favourite daily product. Alternatively, if you usually take a daily product like Every Day or Gut Health Gummies, then you can return to taking this after finishing a course of antibiotics.

Read references

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For Those On Antibiotics (10 capsules) Saccharomyces Boulardii (16 capsules) Every Day MAX (30 capsules) Every Day EXTRA (30 capsules)
Suitability Specific Digestive Specific Digestive General Digestive General Digestive
Format capsules capsules capsules capsules
Billions/CFU 4.5 billion 5 billion 75 billion 20 billion
With FOS/Prebiotic
Price £7.99 £8.99 £42.99 £25.99