Time resolved spectroscopies for human esophageal and breast tissues in vitro have been measured under pulse generation at the wavelength of 514 nm.Lifetime of normal and squamous carcinoma human esophageal tissue have been respectively determined by time resolved detection of laser induced fluorescence rather than the traditional time integrated monitoring technique as 2.09 ns and 1.71 ns,while 2.05 ns and 1.43 ns for the human normal and adencarcinoma breast tissue,respectively.Experimental results show that sufficient difference is obtained between the lifetime of normal and carcinoma tissues,and the lifetime of normal tissues is slower than that of carcinoma tissues.Implications of time resolved spectroscopy for spectroscopic guidance in tissue diagnosis are indicated.