Cannabis is a drug that is widely used for recreational purpose. In most patients undergoing surgery, opioids are the most widely used mode of pain relief, during and following surgery. Anecdotally it has been observed that cannabis users required unexpectedly high doses of opioids. The purpose of this study is to compare opioid requirements between cannabis users and non- users after the surgery. Currently, post-operative opioid doses are determined based on various patient factors such as pre-operative opioid use, patient weight, age and sensitivity to opioids during surgery. Patients' requirements may be underestimated and opioid regimens need to be escalated in the first 24 hours in order to alleviate uncontrolled pain in cannabis users. Better understanding of the impacts of cannabis use on post-operative opioid requirements would help the Acute Pain Service optimize post-operative pain management for patients who use cannabis pre-operatively.

Inclusion Criteria:

1. Consent to participate and signed consent form.
2. Age: 18-65 years.
3. Elective IBD bowel surgery under general anesthesia.
4. PCA use.

Elective IBD bowel surgery under general anesthesia