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.

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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 to take with antibiotics

Perfect for anyone looking to buy a natural friendly bacteria supplement to take alongside a course of antibiotics.

  • Suitable alongside antibiotics Contains three friendly bacteria strains which have been studied in clinical trials on friendly bacteria and antibiotics
  • Scientifically proven Shown to survive stomach acidity and reach the gut alive, even when you take these friendly bacteria with antibiotics
  • Highly researched All three strains have been shown to complement the natural gut bacteria
  • Specific strain action L. rhamnosus Rosell-11 and L. acidophilus/helveticus Rosell-52 have also been shown to increase immune cell activity
  • For daily use Designed for daily use with a typical 10-day course of antibiotics, or can be used for longer periods alongside long-term antibiotics
  • Easy to take Each easy-to-swallow capsule contains 4.5 billion live bacterial cultures; take on the go with no need for refrigeration 
  • A more natural option Vegan and gluten free, with absolutely no artificial flavourings or colourings, and suitable from 4 years of age including during pregnancy
  • Highly recommended From the UK’s most trusted & recommended brand of friendly bacteria supplements.

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

5/5 (21 reviews)
  • I regularly use this product if my clients have to go onto antibiotics I have, on occasion, used this myself too - as well as S Boulardii. Great products from Optibac.

    Nicola Warran- 29th June 2022

  • did the optibac antibiotics due to having a combination of very strong gram negative antibiotics. Optibac was great, kept all the nasty side effects away. Would highly recommend

    Emma Protheroe- 6th December 2021

  • I frequetly use " For those on antibiotics ". This product makes me feel better. I really see a change. I also contacted the customer service dpt to get some info. Very fast reply with all the needed information. Great prouct and great service !

    Stephan B.- 15th November 2021

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Help & advice

Speak to our team of experts (nutritionists, microbiologists and nutritional therapists) any time for free advice, with absolutely no obligation to buy.

Camilla Gray
Camilla Gray DipCNM Nutritional Therapist

Why choose us?

We are the UK's most trusted & recommended brand of friendly bacteria supplements.

† As determined in an independent survey of 1000 British women.

  • How to use

  • Ingredients

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  • 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 (Tracked): £6.95 (Dispatching Friday 30th December)
    Order before 2pm for 1-2 working day delivery to most of the UK*. Orders placed on Friday will be delivered on Monday (next working day). Requires signature.
    Please be aware of Christmas Bank holidays.

    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 Kerry Beeson BSc (Nut. Med.) Nutritional Therapist

 Yes! Taking live cultures with antibiotics is highly recommended.  However, it’s important to select supplements such as Optibac For Those On Antibiotics, which contains strains extensively researched (1,2) alongside this type of medication and shown to reach the gut alive.

(1). Nagulesapillai V. Detection and Quantification of Strain Specific Probiotics in Clinical Fecal Samples of Healthy Adults on Antibiotic Treatment by Quantitative PCR. Poster presentation. 2015;1(1). ( 2). Maydannik V. et al. ‘Efficiency and safety of Lacidofil in children with antibiotic-associated diarrhoea caused by Clostridium difficile.’ Pediatrics, Obstetrics & Gynaecology. 2010;2(3):53-57.
Read More

Live cultures are best taken with food, ideally breakfast, when stomach acidity is closer to neutral. Antibiotics present an additional challenge for most delicate good bacteria, but if you take specific live cultures for antibiotics, such as those found in Optibac For Those On Antibiotics, they are hardy against the effects of this treatment (1) and continue to complement the gut microbiome throughout the course. This means you can still take your friendly bacteria supplement with breakfast as recommended, regardless of when you take your antibiotics! Taking these specific live cultures makes life easy - other live cultures supplements need to be taken at least two hours away from the medication.

(1). Nagulesapillai V. Detection and Quantification of Strain Specific Probiotics in Clinical Fecal Samples of Healthy Adults on Antibiotic Treatment by Quantitative PCR. Poster presentation. 2015;1(1).
Read More

Antibiotic medication can harm most delicate live cultures, so it’s best to choose specific friendly bacteria for antibiotics. Strains such as Lactobacillus acidophilus/helveticus Rosell-52, Lactobacillus rhamnosus Rosell-11 and Bifidobacterium lactis Lafti B94 have been shown to reach the gut alive, even when taken at the exact same time as short or long courses of antibiotic medication (1,2,3). These strains can be found in Optibac For Those On Antibiotics.

(1). Nagulesapillai V. Detection and Quantification of Strain Specific Probiotics in Clinical Fecal Samples of Healthy Adults on Antibiotic Treatment by Quantitative PCR. Poster presentation. 2015;1(1). (2). Maydannik V. et al. ‘Efficiency and safety of Lacidofil in children with antibiotic-associated diarrhoea caused by Clostridium difficile.’ Pediatrics, Obstetrics & Gynaecology. 2010;2(3):53-57. (3). Chernyshov P v. Randomized, placebo-controlled trial on clinical and immunologic effects of probiotic containing Lactobacillus rhamnosus R0011 and L. helveticus R0052 in infants with atopic dermatitis. Published online 2009. doi:10.3109/08910600903444234
Read More

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