BB cream is a makeup product touted to do the job of several products at once, including foundation, sunscreen, skin treatment, concealer, primer and moisturizer. The letters BB stand for multiple things depending on the manufacturer, but it usually stands for beauty balm or blemish balm.
Most beauty balm creams have a sunscreen in them that has an average SPF of 30 or higher. BB creams have a heavier texture than moisturizers and can make some sensitive skin break out. A separate moisturizer generally does a better job. BB creams also usually only come in a couple of shades, which can make matching skin tone an issue.