My husband hallucinated while on morphine in hospital. However, he was also receiving fenegrin (sp?) for nausea and the doctor said the combination of the 2 could cause hallucinations. The vivid dreams, activity while sleeping, and lesser but still hallucinatory images while awake lasted for almost a week following the end of the morphine/fenegren. It was a wild time in the hospital as he got it in his mind on day 2 that he could go home at 1:00, so would get up at each 1:00 and start packing and complaining that I wouldn't take him home. While I laugh about it, it was stressful at the time. Next trip in for chemo we requested NO fenegren and NO morphine. He managed the nausea with other drugs and the pain he managed on his own (he has a high tolerance, fortunately). So, I certainly agree with Michelle that the morphine can cause this, plus other drugs can factor in to the equation.