ABSTRACT
The formaldehyde is the simplest aldehyde. It is an important chemical used widely by industry to manufacture building materials and household products. Everybody can be exposed to small amounts of formaldehyde in air and in some foods. Various dosages of formalin oral administration were used in experimental animals to study its toxicity on the mucosa of different parts of the gastrointestinal tract. A total number of 15 adult male albino rats, two to three months age average and weight between 200 to 250 mg average, at the start of the experiment, were used in the present work. The rats were divided into two groups, control group of 5 animals and experimental one of 10 animals. The experimental group animals received a formaldehyde solution through a gastric tube in a dose of 165 mg/kg/ body weight once daily for consecutive 30 days. The fundic region of the stomach and segments from the jejunum and ileum were extracted, fixed in 5% glutraldehyde and prepared for scanning electron microscopic [examination. The present work revealed indicative changes on the level of scanning electron microscopic findings that observed in the mucosa of the stomach, jejunum and ileum. These findings range from severe damage and ulcer formation in the stomach to mild and moderate toxic effects in the jejunum and ileum including edema, congestion partial destructions in the form of fenestrations and cracks or even complete and partial fragmentations of their villi