CBD can help with anxiety and THC can help with mood swings, irritability, and low resilience (your ability to handle stress). Both can help relax the uterine muscle where cramps occur, and alleviate many PMS symptoms—but if you don’t like the altered feeling of THC, you can get a lot of PMS relief just using CBD.
CBD acts as an anti-inflammatory and antioxidant agent, and a muscle relaxer. It’s thought to decrease anxiety and have a calming effect.
https://goop.com/wellness/sexual-health/can-cannabis-help-with-pms