Caulk generally comes in two different types: silicone and acrylic latex.
Acrylic latex caulk should be used if the area you are caulking does not see a lot of water, or you need to use a colored caulk or one that can be painted to match. Acrylic caulk works well for painting applications as it fills in any gaps between walls, ceilings, and woodwork trim.
It cleans up well and provides a clean, neat seal.
Silicone caulk, is often referred to as rubberized silicone caulk, remains flexible for most of its lifetime without peeling, cracking, or distorting. It will maintain and keep a waterproof barrier against moisture much longer than acrylic caulking as a result and typically is more expensive. This trait makes silicone the caulking of choice around showers, bathtubs, sinks, and toilets. Additionally, due to its long-lasting nature and its ability to retard moisture and maintain its strength, silicone caulking is an excellent choice for outdoor use and for protecting the home from outdoor wet-weather conditions. However, silicone caulk cannot be painted, and generally only comes in neutral colors like clear or white.
For most caulking applications, homeowners will either use an acrylic latex caulking material or one made from silicone compounds.