"Drink this and all of Link's LIFE hearts will turn red. Red water turns blue when Link sips it. Drink the blue water and that's the last of the water."
The Legend of Zelda manual

2nd Potion, also known as Red Water of Life, is an item from the The Legend of Zelda. This magical potion restores all of Link's Hearts. When 2nd Potion is consumed, it becomes Life Potion, which can also refill Link's Hearts. Both potions will also cure him of the jinx placed on him by red Bubbles.

In order to purchase 2nd Potion, Link first must obtain a Letter from an Old Man. Prior to acquiring this Letter, Link may come across caves in which he finds an Old Woman who does not speak. Once he shows the letter to any one of these women, they all become willing to sell him 2nd Potion and Life Potion. 2nd potion costs sixty-eight Rupees, and Life Potion costs forty Rupees. Also, when Link has a Life Potion in his inventory and purchases another one, it becomes a 2nd Potion.

Link can encounter Old Men who offer him a choice of either taking a Heart Container or a 2nd Potion. Taking the potion is inadvisable, however, as it can be purchased and Heart Containers cannot.

See also