hello Josephine... thank you for posting your query in healthcaremagic.com.... it is assumed that your mother is suffering from osteopoosis... hence she is advised to take actonel which is risedronate..... see risedronate is one of the first line therapies for osteoporosis... and alongwith, generally vitamin d and calcium supplements are added in elderly patients as an adjunct... so it is a good combination....she can definitely take them together without any possible drug interaction or adverse effect.... hope this was helpful... regards