It's fine to do as a premed degree, except you'll be spending 10 years at university should you proceed all the way to becoming a doc. Then there is intern and registrar years, meaning expect to be in your early 30s before you earn >$50k a year.
The people I know who did Comm/Sci and managed to use both ended up in roles like management accounting/finance in a pharmaceutical company. Usually people just take one and run with it (e.g. Commerce).