Portulaca, also known as Portulaca oleracea or purslane, has a long history of use in traditional medicine systems, particularly in Asia, the Middle East, and parts of Europe. Traditional uses include the treatment of various inflammatory conditions, with some sources specifically noting its use for soothing mucous membranes in the gastrointestinal and respiratory tracts. Purslane is rich in mucilage, which is a type of soluble fiber known for its soothing and protective effects on mucous membranes. This mucilage may help coat and calm irritated mucosal surfaces, which could explain its traditional use for coughs, sore throats, and mild digestive irritation.

However, while laboratory studies have confirmed anti-inflammatory, antioxidant, and wound-healing properties of Portulaca extracts, there is minimal direct scientific evidence specifically validating its efficacy for supporting mucus membranes in humans. Most scientific research focuses on its nutritional content (such as omega-3 fatty acids and vitamins) and general anti-inflammatory effects, rather than targeted studies on mucosal tissues. Therefore, the rating reflects the presence of traditional precedent and plausible mechanisms, but a lack of robust clinical trials.