Mother's milk tea is a mild galactagogue (a substance that can be used to increase milk supply). Its main milk-boosting ingredient is fenugreek, an slightly bitter-tasting. Some moms find that sipping a few cups of this tea a day is an easy way to help their bodies make more milk. Some drink it hot, some drink it iced, and some mix it with apple juice.
You can find mother's milk tea at many drugstores and grocery stores, but remember that the tea is meant for boosting your supply — not for maintaining it. Once your milk is at a level that suits you and baby, you can give the herbal remedy a rest. (Most women find that their supply stays up once they stop taking fenugreek.)
One disadvantage of teas is that there is no way to know the exact dose you are getting. This may be fine if you're just giving your supply a little boost, but if you're really focusing on increasing your supply, it's a better idea to take a form where the dosage is known, controlled and, most likely, higher. In this case, look for fenugreek capsules, powder or tinctures. Talk to your doctor before taking this or any other supplements or medications (herbal or not).