What is a bezoar and how does it affect human?

Hair ball. Some people pick hair and eat it. The ball can collect and enlarge in the stomach or intestine. Worst case, blockage, at which point it must be removed!
Bezoar. Gastric bezoars are usually asymptomatic, although unspecific symptoms may appear. Symptoms include abdominal pain, nausea, vomiting, anorexia, weight loss, feeling of gastric fullness and foul breath. Phytobezoars are composed of vegetable matter and are the most common type, trichobezoars are composed of hair, and pharmacobezoars are composed of ingested medications.
Bezoar. Gastric bezoars are usually asymptomatic, although unspecific symptoms may appear. Symptoms include abdominal pain, nausea, vomiting, anorexia, weight loss, feeling of gastric fullness and foul breath. Phytobezoars are composed of vegetable matter and are the most common type, trichobezoars are composed of hair, and pharmacobezoars are composed of ingested medications.
Bezoar. Gastric bezoars are usually asymptomatic, although unspecific symptoms may appear. Symptoms include abdominal pain, nausea, vomiting, anorexia, weight loss, feeling of gastric fullness and foul breath. Phytobezoars are composed of vegetable matter and are the most common type, trichobezoars are composed of hair, and pharmacobezoars are composed of ingested medications.