Calendula is a marigold plant that has long been used for its skin health benefits, such as helping with wound healing.1 Calendula petals are rich in naturally occurring compounds called flavonoids. These compounds are said to have anti-inflammatory, anti-thrombogenic, antidiabetic, anticancer, and neuroprotective effects.2 This article will go over how calendula is used. You will also learn about the possible side effects and risks of using calendula.