Nurse less, try OTCs
If you have a problem with oversupply and are still nursing, reducing the frequency/length of nursing will decrease milk production over time.
Peppermint and sage teas may help and antihistamines like diphendydramine and Cetirizine
and loratidine might decrease your supply. If you have stopped nursing completely and want to stop lactating, bromocriptine
is sometimes prescribed by docs for this.