Breastfeeding, like most things in life, has its ups and downs. Many nursing mothers experience a decrease in their milk supply especially working moms who pump often since pumping doesn't always provide the same strong suction that the infant does.
Whenever I felt my supply decreasing, I turned to Mother's Milk Tea to remedy the problem. While some of it might have been mental, I credit the tea for the return of my milk rivers. At $5 for a box of 16 bags, it was worth a shot and was pretty tasty.
As with most things you consume while nursing, consult your physician before drinking.