Marigold, most commonly referring to Calendula officinalis, has a long history of traditional use for treating skin and mucosal conditions, including canker sores (aphthous ulcers). In traditional European and herbal medicine, calendula preparations—such as tinctures, teas, and mouth rinses—have been used for their purported anti-inflammatory, antiseptic, and wound-healing properties. These effects were believed to help soothe oral lesions and promote faster healing when applied topically or used as a mouthwash.

Scientific validation for these uses is limited but not absent. A small number of clinical studies and laboratory investigations suggest that calendula extracts may possess anti-inflammatory and antimicrobial properties, potentially aiding in the management of minor oral wounds. For example, a few randomized controlled trials have shown that calendula mouthwash can reduce pain and healing time in patients with oral mucositis or aphthous ulcers, though the overall quality and size of these studies are limited. No large-scale, definitive studies exist to firmly establish efficacy.

In summary, the use of marigold (calendula) for canker sores is primarily rooted in traditional herbal practices, with a modest but growing body of scientific research providing some support. However, more rigorous clinical trials are needed to fully validate its effectiveness for this specific condition.