As the world's population ages, those suffering from diseases of the elderly will increase. Health care expenditures will increase rapidly and become unaffordable for governments around the world. New technology and new models for patient healthcare must be found to relieve the pressure on finances and society. In-home pervasive networks may assist residents by providing memory enhancement, control of home appliances, medical data lookup, and emergency communication. Cooperation between wireless sensor networks and existing consumer electronic infrastructures can assist in the areas of health care and patient monitoring. This will improve the quality of life of patients, provide early detection for certain ailments, and improve doctor-patient efficiency. In this paper we first detail some basal concepts of wireless sensor networks. The possible security issues, privacy issues and legal issues are discussed in the second part. The prospects and functions of next generation smart homecare based on wireless sensor networks are discussed in the last part.