Plantago (commonly Plantago ovata, known as psyllium) is primarily used as a source of dietary fiber. Its use in supporting or managing diverticulitis or diverticular disease is supported by some scientific evidence, though the evidence is not robust or disease-specific. Psyllium is a soluble fiber that helps to increase stool bulk and soften stools, making them easier to pass. This can decrease colonic pressure and may help prevent the formation of new diverticula and reduce the risk of complications in people with diverticulosis (the presence of diverticula without inflammation).

Guidelines and clinical sources, such as the American Gastroenterological Association, recommend a high-fiber diet for patients with diverticular disease to reduce symptoms and prevent progression. Psyllium is commonly prescribed or recommended as a fiber supplement to achieve this. However, for acute diverticulitis (active inflammation), increasing fiber intake is not recommended until the inflammation subsides.

Several small studies and reviews suggest that psyllium supplementation can help with symptoms like constipation and abdominal discomfort in people with diverticulosis. These effects are mainly attributed to improved bowel regularity and softer stools. Nevertheless, the direct evidence of efficacy for preventing diverticulitis attacks or treating acute diverticulitis is limited, and most recommendations are extrapolated from its general benefits for bowel health.

In summary, the use of Plantago (psyllium) for diverticular disease is scientifically supported for general management of diverticulosis, though high-quality, condition-specific evidence for diverticulitis is lacking.