Abstract Oesophagogastric ulceration is a common disease in pigs. It is almost exclusively confined to the non-glandular pars-oesophagea. The prevalence of this gastric ulcer has been raised globally. Vitamins and trace elements play important roles in different physiological processes in pigs. Requirements of these elements will depend on ages, physiological statuses and feeds. Hence, there were only limited studies conducted on Methyl methionine sulfonium chloride (also known as Vitamin U), particularly in barrows and gilts. Thus, we investigated the beneficial effects of Vitamin U supplementation on the gastric ulcer problem of finishing pigs. One hundred-forty [(Landrace × Yorkshire) × Duroc] barrows and gilts (86.5 ± 1.5 kg) were used in a 28-d experiment in a randomized complete blocked design and assigned to TRT1 (basal diet); TRT2- (basal diet + stress), TRT3 (basal diet + 0.05 % Vitamin U), TRT4 (basal diet + aspirin 15g (3 days) + stress), and TRT5 (basal diet + aspirin 15g (3 days) + stress + 0.1 Vitamin U ), respectively. The active ingredients of Vitamin U: 50mg/g, MgO 60mg/g, Na2CO3 70mg/g. TRT 5 group pigs showed a significant increase (P < 0.05) in final body weight and average daily gain (ADG) compared with other groups. However, there was no significant difference in body condition scores between treatment groups (P > 0.05). Stomach keratinization scores were significantly greater in TRT2 and 4 than in TRT 3 (P < 0.05). In summary, the addition of Vitamin U (stayvill) to the diet improved the degree of gastric ulcer to a certain extent and effectively improve growth performance in finishing pigs.