Calpis

Calpis (カルピス Karupisu?) is a Japanese uncarbonated soft drink, manufactured by Calpis Co., Ltd. (カルピス株式会社 Karupisu Kabushiki-gaisha?), headquartered in Shibuya, Tokyo. The beverage has a light, somewhat milky, and slightly acidic flavor.

The drink is sold as a concentrate which is mixed with water or sometimes milk just before consumption. It is also used to flavor kakigori (shaved ice) and as a mixer for cocktails and chuhai.

It was first marketed on July 7, 1919. It quickly became popular in pre-war Japan as its concentrated form meant it kept well without refrigeration.

In Blood+ Manga
Calpis is shown to be Saya's favorite drink in the manga. She drinks a whole bottle of undiluted calpis after her awakening in Okinawa. She can drink two bottles at a stretch without any side-effects.

After the destruction of Red Shield HQ, Kai and others are shown to be living in New York. Lewis once brings a bottle of calpis from the only import center. Seeing that, Kai assumes Saya must be nearby if she is in New York, knowing how much she loves calpis. After running into chiropterans, Kai's assumption is proved true by Saya who shows up to save him.