Substituted 2-aminomethyl-4-phenyl-1,3-benzodioxans and derivatives thereof have been found to possess valuable anticonvulsant and antiarrhythmia activity in mammals. For example, cis-6-chloro-2-methylaminomethyl-4-phenyl-1,3-benzodioxan hydrochloride possesses potent anticonvulsant activity while cis-2-isopropylaminomethyl-4-phenyl-1,3-benzodioxan hydrochloride has potent antiarrhythmia activity.