According to Barb at www.thegardenhepler.com, their petals have been used to treat not only skin wounds, but gastritis, cramps, warts, and taken as a tea, it has been used to treat stomach ulsers and inflammation.
Calendula is fast becoming one of my favorite flowers because of all its uses. They add color to any garden with their bright, cheerful orange-yellow flowers that bloom from March to first frost. They re-seed themselves. You can collect some of the seeds after they dry on the stem to a hardened half circle where the petals used to be. The seeds look like a hard worm, to me. Make sure the seeds are totally dry, then store them in an envelope in a cool dry place until Spring. Don't forget to label and date them. Here is a good place to get 50 Organic Calendula seeds for only $2.95: http://coldfusion.affiliateshop.com/AIDLink.cfm?AID=115164&Redirect=/seeds/seeds.html