Wilberforce had planned to introduce a motion giving notice that he would bring forward a bill for the Abolition of the Slave Trade during the 1789 parliamentary session. However, in January 1788, he was taken ill with a probable stress-related condition, now thought to be ulcerative colitis. It was several months before he was able to resume work, and he spent time convalescing at Bath and Cambridge. His regular bouts of gastrointestinal illnesses precipitated the use of moderate quantities of opium, which proved effective in alleviating his condition, and which he continued to use for the rest of his life.