Getting ink poisoning from tattoo ink is very rare, as most ink poisoning occurs when people ingest more than an ounce of regular writing or printer ink. Nausea and vomiting are common symptoms of traditional ink poisoning, but few people experience these symptoms from tattoo ink. The composition of tattoo ink is not regulated and, in order to protect trade secrets, tattoo artists are not required to reveal ink ingredients.
Allergic reactions to components in the ink ingredients are often confused with ink poisoning. Because tattoo artists can keep the ingredients a secret, it's very difficult to predict if a person will have a negative reaction to tattoo ink. An artist can conduct a quick skin test by rubbing the ink onto the skin and waiting a few minutes to see if redness, itchiness or swelling appears.
Bacterial infections can also be confused with ink poisoning and occur when a tattoo artist does not properly clean all equipment and needles or uses the same needle on multiple clients. Severe pain, redness underneath the skin or pockets of pus around a tattoo often signify a bacterial infection rather than ink poisoning. It is also possible to contract hepatitis or HIV from dirty tattoo needles.