“Because pineapple is a great meat tenderizer, eating too much can result in tenderness of the mouth, including the lips, tongue and cheeks,” Flores said. “But, [it] should resolve itself within a few hours.” If it does not, or if you experience a rash, hives or breathing difficulties, you should seek a medical help immediately. You could have a pineapple allergy.
Flores pointed out a possible negative to pineapple’s high levels of vitamin C. “Because of the high amount of vitamin C that pineapples contain, consuming large quantities may induce diarrhea, nausea, vomiting, abdominal pain or heart burn,” she said.
Additionally, extremely high amounts of bromelain can cause skin rashes, vomiting, diarrhea, and excessive menstrual bleeding, according to the University of Maryland Medical Center. Bromelain can also interact with some medications. Those taking antibiotics, anticoagulants, blood thinners, anticonvulsants, barbiturates, benzodiazepines, insomnia drugs and tricyclic antidepressants should be careful not to eat too much pineapple.
Eating unripe pineapple or drinking unripe pineapple juice is dangerous, reports the horticulture department at Purdue University. In this state, it is toxic to humans and can lead to severe diarrhea and vomiting. Eating a great deal of pineapple cores can also cause fiber balls to form in the digestive tract.