Swallowing the blood of a person with AIDS can potentially cause transmission. If a person with AIDS is not on antiretroviral therapy, the blood can contain relatively high amounts of HIV, and if the blood comes into contact with the oral cavity and the mucous membranes of the digestive tract of another person, there is a risk of transmission. If the blood comes in contact with mucous membranes, the risk of HIV transmission from such an exposure is about 0.09%. This is not too high overall, but if the amount of HIV is particularly high in the blood of a person with AIDS, and the person who swallowed the blood has ulcers and breaks in the oral mucosa, then the likelihood of transmitting AIDS is going to rise. However, if the AIDS patient has undergone relatively good antiviral treatment and the amount of HIV in the blood is very low, the likelihood of this situation causing infection will also be very small, significantly less than 0.09%.