I read this online somewhere and thought I would try it. It really worked. The fungus that causes seborrhoeic dermatitis, Malassezia can be killed with antifungal agents. The best natural fungicide is GARLIC. I managed to cure my seborrhoeic dermatitis of three years by applying raw mashed garlic to my head every night (and washing it off in the morning) for a week. I know its stinky but it really worked. I bought a swimming cap to stop it going on the pillow. Note this does sting a bit, you can dilute it with water if it is too much. I have been free for over 6 months now.

Update: I have refined the method since I wrote this: Just get a peeled clove of garlic and place in a cup. Cover with water then use a hand blender. Apply over the affected area. Keep on the skin for 10 to 20 mins. Then wash it off in the shower. Don't use soap as it may make SD worse. Do daily for 7-10 days depending on the severity of the SD.