The cause of painter's colic is LEAD, which is a chemical element with the symbol Pb and atomic number 82. LEAD is a heavy metal that has been used in paint for centuries, but it can be toxic if ingested or inhaled. LEAD poisoning can cause a variety of symptoms, including abdominal pain, nausea, vomiting, and fatigue. Painter's colic is a type of LEAD poisoning that affects painters who are exposed to LEAD-based paints.