The herbal preparation STW 5 positively influences changes in intestinal microbiota induced by functional dyspepsia or ulcerative colitis in rats.

The herbal preparation STW5 (Iberogast®) is a multi-component multi-target herbal preparation consisting of hydro-alcoholic extracts of bitter candytuft, lemon balm, chamomile, caraway fruit, peppermint leaf, Angelica root, milk thistle, celandine herb, and licorice root. It has been shown to be clinically effective in irritable bowel syndrome1 and functional dyspepsia2 as well as experimentally in inflammatory bowel disease3. Since many clinical gastrointestinal conditions have been linked with changes in intestinal microbiota, we have studied such changes in models of functional dyspepsia and ulcerative colitis. The effect of STW5 on gut microbiota in normal rats and in established FD and colitis rat models was studied by assessing changes in selected major bacterial phyla using quantitative Real Time-PCR (qPCR). Ulcerative colitis was induced in rats by feeding them 5% DSS while functional dyspepsia was induced by subjecting rats first to neonatal maternal separation followed by restrained stress at maturity. In normal animals STW5 dramatically increased the relative abundance of Bacteroidetes, Bacteroides and Prevotella phyla of rat gut microbiota but a decrease in Bifidobacteria, Actinobacteria and Clostridium. Treatment with STW5 induced a dramatic increase in Lacobacillus and Mathanobrevibacter populations. Changes in the microbiota Prevotella and Enterococcus induced by the stress models were prevented by STW5 administration. The findings lend support to the use of STW5 in the gastrointestinal conditions mentioned by influencing favourably the derangements in the intestinal microbiota caused by them.

[1] Schmulson MJ, Nature Clinical Practice Gastroenterology & Hepatology, 2008, 5, 136 – 137,

[2] Madisch A et al, Aliment Pharmacol Ther, 2004, 19: 271 – 279,

[3] Wadie W et al, Int J Colorectal Dis, 2012, 27:1445 – 53.