Omeprazole and VomiSan – for stomach acid and the mucous

19. January 2021 — von Daniela Diepold

Omeprazol is a well-known medicine for stomach ulcers that protects the stomach. VomiSan is a complementary feed for cats and dogs that naturally supports the gastric mucosa and the stomach and throat areas. Both support animals’ digestive tract. But what is the difference between the two?


Omeprazole is a proton-pump inhibitor medication (PPI), a so-called “prodrug”. It is converted into its active form as a sulfenamide derivative first in the acidic environment of the gastric mucosa. Omeprazole inhibits the proton-pomp: at acidic pH values, the active ingredient accumulates in the parietal cells of the gastric mucosa and there inhibits the H+/K+/ATP – the energy source of the proton pump. This blocks the basic acid secretion in the stomach. At the same time, omeprazole has no effect on the H+/K+/ATP of other cells as their pH is too high for omeprazole to accumulate.

Acid-reducing and cytoprotective

In addition to its acid-reducing properties, omeprazole has a cytoprotective effect by increasing the prostagladin secretion of the mucosal cells. The acidity is more effected by the active substance of omeprazole than it is by the secretion volume.

Indicated use

Omeprazole is used for reflux esophagitis, gastritis and gastrointestinal ulcers.

Common side effects

Due to the high selectivity of omeprazole in relation to the H+/K+/ATP, side effects of the medicine are rare. The active substance appears to be well-tolerated in therapeutic doses by cats and dogs. However, because of a possible gastrin-induced tumorigenic effect, long-term treatments should be avoided. Side effects such as colic, vomiting and flatulence can occur.


With VomiSan, the special combination of ingredients soothes the gastric mucosa thereby offering protection against substances that attack and irritate the stomach wall. VomiSan can be given during and after taking painkillers or antibiotics. It is also suitable for “grass eaters”, “snackers”, “snow eaters” and “sea water drinkers”.

Common side effects

VomiSan is suitable for long-term administration without any side effects.

Phytotherapeutic substances

Marshmallow root (althaea radix)
Marshmallow comes from the mallows family. Marshmallow roots contain up to 20% mucilage, made up of three main groups of ingredients: neutral glucan, neutral arabinogalactan, acidic rhamnogalacturon. The mucus content is highly dependent on the season, reaching the highest levels in late autumn and the lowest in spring. The marshmallow polysaccharides adhere to the mucous membranes and inhibit mucociliary transport.

Dill fruit (anethum fructus)
Dill comes from the umbelliferae family, and contains 2.5-4% essential oil. The main component of dill fruit is carvone, a monocyclic menoterpene ketone present in dill essential oil. Essential oils are found in various medicinal plants as aromatic steam volatile substances. These often complex mixtures of lipophilic substances often contain terpenes and phenylpropanes. Essential oils are primarily used for local irritation and hyperaemia, and connects directly to the smooth muscles of the gastrointestinal tract.

Psyllium husk (plantago psyllium semen)
The peel of Indian psyllium has a strong natural swelling effect. The seed can absorb up to 40 times its own weight in water – once in contact with liquid, it forms a protective layer of mucus. In the stomach, this covers the stomach lining and esophagus like a film. In the gut, moreover, psyllium husk can bind excessive fluid. The resulting increase of filling volume in the gut triggers defecation through a stretched, long-term stimulus. In this way, psyllium husk shortens the transit time of the faeces through the gut.


  • Clinic Pharm:
  • Österreichische Gesellschaft für Phytotherapie:
  • Phytotherapie in der Tiermedizin (Brendieck- Worm, Thieme, 2018)
  • Lehrbuch der Pharmakologie und Toxikologie für die Veterinärmedizin (Richter, Thieme, 2016)