Fenugreek is an herb that helps raise milk supply. It's been used for centuries in cultures across the world, both as a galactagogue (milk-making aid) and as a spice (you'll find it in curry powder, for example). Nobody really knows how it helps moms make more milk, but it does.
You can find fenugreek in capsule, powder, seed, tincture, or tea form. Use fenugreek with caution if you have a history of diabetes or hypoglycemia, asthma, abnormal menstrual cycles, peanut or chickpea allergies, migraines, blood pressure problems, or heart disease. And, of course, always discuss any supplements — herbal or not — with your doc before starting treatment.