O'Sullivan captured two more ranking titles in the 1997–98 season. By beating three-time defending champion Stephen Hendry 10–6 in the final, O'Sullivan won his second UK Championship title. O'Sullivan also triumphed at the Scottish Open by defeating John Higgins 9–5 in the final. For the third year in a row, O'Sullivan made the final of the Charity Challenge. He was defeated, like the year previous, in a final frame decider, 8–9 to John Higgins. For the first time in three years O'Sullivan did not reach the final at the Masters, losing to Steve Davis. After defeating Ken Doherty 9–3 in the final of the Irish Masters, a post-match drug test found traces of cannabis in his system. O'Sullivan was stripped of the title, forfeited the prize money and the title was awarded to Doherty by the WPBSA. O'Sullivan reached the World Championship semi-finals for the second time in his career, but lost 9–17 to eventual champion John Higgins.