A therapy or medical treatment is the attempted remediation of a health problem, usually following a medical diagnosis. Both words, treatment and therapy, are often abbreviated tx, Tx, or T.
As a rule, each therapy has indications and contraindications.  There are many different types of therapy.  Not all therapies are effective.  Many therapies can produce unwanted adverse effects.
Treatment and therapy are often synonymous, especially in the usage of health professionals. However,  in the context of mental health, the term therapy may refer specifically to psychotherapy.