胃炎分为糜烂性胃炎和非糜烂性胃炎，也可根据胃累及的部位进行分类(如贲门，胃体，胃窦)。根据炎性细胞的类型，在组织学上可将胃炎进一步分为急性胃炎和慢性胃炎。然而尚无一种分类方法与其病理生理完全吻合，各种分类尚有重叠。俗话说：“是药三分毒。”绝大多数药物均要通过胃肠系统进行传递、消化和吸收，所以胃肠道首当其冲地受到某些药物的刺激及损害。
据临床资料表明，因用药不慎而导致胃炎、胃肠道溃疡和出血等疾病的，约占胃病总人数的三分之一以上，且有逐年增加的趋势。
临床发现，引起胃炎的常用药物主要有水杨酸制剂（阿司匹林、复方阿司匹林）、保泰松、消炎痛、肾上腺皮质激素、抗菌消炎药物（如复方新诺明、四环素、红霉素），其他药物如洋地黄、利血平、抗组织胺药等，也可引起胃炎的发生。为什么会引起胃炎呢主要有以下几方面原因：
1．抑制胃粘膜分泌前列腺素E。前列腺素E有保护胃粘膜的作用，当前列腺素E抑制或分泌减少时，可造成胃粘膜损伤，发生炎症，常常是服用保泰松、消炎痛之后。
2．降低了胃粘膜腺体的分泌，改变了腺体分泌的成分，削弱胃粘膜屏障的保护作用，增加胃酸和胃蛋白酶的分泌，抑制了胃粘膜上皮细胞的再生。如长期大量服用强的松，即可引起胃炎和胃肠道溃疡，甚至穿孔。
3．破坏了胃粘膜上皮细胞的脂蛋白层。长期口服刺激性药物（水杨酸制剂）可引起氢离子因渗至粘膜内，扩大粘膜损伤，促使胃粘膜被胃蛋白酶消化，造成糜烂和出血。同时，水杨酸在胃内酸性环境下，量多时能直接破坏胃粘膜上的上皮细胞的脂蛋白层，以致胃粘膜屏障被破坏，导致炎症的发生。
有胃炎史者应尽量选择肠溶性的药物，如肠溶阿司匹林、红霉素等，或改为注射，尽量不口服。
服用非肠溶性药物的患者，一定要在饭后服药。长期服用有刺激性的药物者，一定要同时服用保护胃粘膜的药物（如氢氧化铝之类），还要控制剂量。
译文:
What medications are harmful to stomach
Gastritis can be categorized into two kinds: erosive gastritis and non-erosive gastritis, and it can also be classified according to the body part which the stomach affects (such as the cardia, corpora ventriculi, antrum of stomach). Based on the types of the inflammatory cells, gastritis can be further categorized into acute gastritis and chronic gastritis in histology. However, there is no means of classification so far can tally exactly with the pathophysiologic symptoms of the disease and different classifications still may overlap. There is an old saying goes that every medication has side effect. Most medication need to be transmitted, digested and absorbed through the gastrointestinal system, so the gastrointestinal tract bears the brunt of being irritated and harmed by certain medication.
Clinical data shows that the number of patients who suffer from gastritis, gastrointestinal ulcers and haemorrhage or other such kind of disease due to their using medications inadvertently, accounts for over one third of the total number of gastritis patients, and it tends to increase year by year.
Clinical treatments indicate that the common medications which cause gastritis are Salicylic Acid preparation (Aspirin, Acetyl salicylic acid compound), Phenylbutazone, Indomethacin, adrenal cortical hormone, antibacterial and anti-inflammatory medications (Trimethoprim-sulfamethoxazole, Tetracycline, Erythromycin), and other medications such as Digitalis, Reserpine, antihistamine drug; can also cause gastritis. The reasons why those medications can cause gastritis are explained as follow.
1. Those medications inhibit the secretion of prostaglandin E from stomach lining. Prostaglandin E can protect the stomach lining. When the secretion of Prostaglandin E was inhibited or reduced, it can result in damage to the stomach lining and cause inflammation, and this often occurs after taking Phenylbutazone or Indomethacin.
2. Those medications reduce the secretion from stomach lining gland; change the component of the secretion from stomach lining gland; weaken the protective function of the stomach lining; increase the secretion of gastric acid and pepsin; inhibit the reproduction of epithelial cells of the stomach lining. Taking prednisone in large dosage for long time can cause gastritis, gastrointestinal ulcers, even stomach perforation.
3. Those medications destroy the lipoprotein in the epithelial cells of the stomach lining. Taking stimulant medication orally for a long time can cause hydrogen gene penetration into stomach lining, expansion of damage to stomach lining, and lead to the assimilation of the stomach lining by pepsin; thus result in erosion and haemorrhag. At the same time, in the acid environment in the stomach, too much salicylic acid can directly destroy the lipoprotein in the epithelial cells of the stomach lining, and make the stomach lining protection being destroyed and cause the gastritis.
Patients with a history of gastritis should choose enteric medication, such as Aspirin, Erythromycin, or choose injection, and try not to choose oral administration
Patients who take non-enteric medication must take it after meal. People who take stimulant medication orally for a long time must take medication that can protect stomach lining such as aluminum hydroxide) at the same time and the dosage must be controlled.