**Cannabidiol in Sickle Cell Disease Study** This study is testing how safe and effective cannabidiol is for adults with sickle cell disease (SCD). Sickle cell disease is a blood disorder that can cause pain and other health problems. Cannabidiol is a compound from the cannabis plant that is being tested to see if it can help reduce inflammation. In the study, some participants will get cannabidiol and others will get a placebo (a pill that doesn't have any medicine in it) to compare results. About 52 people will be part of this 4-week study. Participants should not be in pain crisis when joining and must test free from cannabis use before starting. The study will check if cannabidiol can lower inflammation by measuring a substance in the blood called TNFα. **Key Points:** - Study duration is 4 weeks with daily doses. - Participants must be at least 18 years old and not currently using cannabis. - You must be willing to avoid cannabis and use birth control if needed. **Eligibility includes** adults with SCD who aren't pregnant, are stable on current SCD treatments, and do not have certain health issues. Participants must agree to avoid cannabis during the study.