Oral soft tissue ulcers are common disorders of horses, but it is unclear if their prevalence is increased by riding horses with a bit and bridle. Oral examinations were performed on 113 horses and ponies, all which had received routine dental floating, that were divided into four groups depending on when they had last been ridden with a bit and bridle. The subjects comprised: group 1, a randomly selected population of ridden horses; group 2, a group of horses examined after being rested at pasture for 5 weeks; group 3, the previous group following 7 weeks of riding with a bit and bridle, and group 4, brood mares that had not been ridden for at least 11 months. Lip and intraoral soft tissue lesions were recorded at seven pre-determined locations, with lesions classified as large or small; acute or chronic. The examinations showed that horses that were currently being ridden with a bit and bridle had a significantly higher prevalence of large and acute buccal ulcers opposite the maxillary Triadan 06 teeth and of the commissures of the lips, as compared to horses that were not being currently ridden. It was concluded that using a bit and bridle can cause oral ulceration even in horses that have regular prophylactic dental floating. It is suggested that riding tack should be individually fitted for each horse and also that prophylactic dental treatments should be individually adapted for each horse.