Which natural antifungal thing is best for scalp seb der ? which topical natural remedy is best for scalp seborrheic dermatitis ?

NONE: "Natural" does not mean anything is useful or safe. Lead, cyanide, monoxide, and poison ivy are all natural. There are perfectly good shampoos found everywhere which can be used daily if desired. They include Head & Shoulders, Selsun, Nizolal, and others. The generics are just as good. DHS makes several. T-Sal and T-Gel are in every store.