A lacto vegetarian diet is a vegetarian diet that includes dairy products such as milk, cheese, yogurt, butter, cream, and kefir but excludes eggs. "Lacto" originates from the Latin word for milk. Within Indian culture this diet is often what is meant by the term vegetarian This may be because the egg is viewed as a potential animal, and should not be eaten, or because of outrage at the egg industry. In general, lacto vegetarians are feel more strongly about animal rights than lacto-ovo vegetarians. (lacto-ovo vegetarians who are very concerned about animal rights) Lacto and lacto-ovo vegetarians seem to prefer reform of the egg and dairy industry rather than the elimination of them. Lacto vegetarians may have some trouble with what they can and can't eat, since eggs are sometimes hidden in products such as pasta and ice cream, where you would not suspect eggs. However, it is much easier for a lacto-vegetarian than a vegan

A lacto-ovo vegetarian is a vegetarian who eats neither red meat nor poultry, but does eat animal products such as eggs and dairy products. This is justified because the animal does not die to produce the milk and eggs. Most lacto-ovo vegetarians are so for ethical reasons, although there are a few who simply do not like the taste of meat. Most lacto-ovo vegetarians do not eat gelatin and fish, although you will find a few who do. Some lacto-ovo vegetarians avoid leather, and other products which obviously harmed animals, while others are not as much less concerned with this as that they "cannot" give up such things, or feel that this would be too extreme. In general, a lacto-ovo vegetarian is your "basic vegetarian."

In the Western world lacto-ovo vegetarians are the most common type of vegetarian. Generally speaking, when one uses the term vegetarian a lacto-ovo vegetarian is assumed. Lacto-ovo vegetarians are well-catered to in restaurants and shops, especially in Europe and metropolitan cities in North America.
Some lacto-ovo vegetarians who are motivated by ethical reasons may avoid fertilized eggs as well as caviar, feeling that both involve the killing of beings or torture and exploitation of source animals. Most vegetarians motivated by ethics would only use "Free Range" eggs.

A lacto-ovo vegetarian usually doesn't eat poultry, meat or fish. However, cross-culturally, different cultures recognize vegetarianism differently. For example, there are many Japanese vegetarians consider fish to be vegetarian, and Indian vegetarians who consider eggs to be non-vegetarian.