Marigold, particularly the species Calendula officinalis and Tagetes erecta (also known as Mexican marigold), has a history of use in eye health, mainly supported by scientific interest in its constituent lutein and zeaxanthin. These carotenoids are abundant in marigold flowers, especially Tagetes erecta, and are known for their role in filtering harmful blue light and acting as antioxidants in the retina. Several clinical studies have shown that supplementation with lutein and zeaxanthin can help support eye health, particularly in reducing the risk of age-related macular degeneration (AMD) and possibly cataracts. Marigold extracts standardized for lutein are widely used in commercial eye health supplements for this reason.

However, it is important to note that the evidence primarily applies to purified lutein and zeaxanthin, not to marigold as a whole plant or as a traditional herbal preparation. Historical or folk use of marigold for eye issues is limited and not well-documented. The clinical evidence supporting lutein and zeaxanthin supplementation is rated as moderate (hence the score of 3), as most benefits are seen in populations at risk for AMD, not the general population, and the effect size is moderate. The use of marigold-derived lutein for eye health is thus scientifically validated, but not all marigold preparations are effective or recommended for this purpose.