Reflectometric technique for analyzing urine strips represents a simple, fast and inexpensive method, with no risk and discomfort for the patient. In the present paper, the authors conducted a retrospective study on the possible association between lichen planus (LP) and a number of pathological conditions that produce changes of urine metabolites. A retrospective study was made on 77 patients with LP (49 cases of cutaneous LP - CLP, 28 cases of oral LP - OLP) who were diagnosed and treated in the dermatology department of Victor Babes Hospital for Infectious and Tropical Diseases. The quantification of certain urine metabolites in the spontaneous urine through reflectometric technique may reveal liver diseases (urobilinogen, bilirubin), kidney diseases (erythrocytes, proteins, albumin, creatinine, albumin/creatinine ratio, urine specific gravity, pH), metabolic disorders (glucose, ketones, pH, ascorbic acid) and urinary diseases (leucocyturia, nitrites, proteins, erythrocytes). The evaluation of the patients included clinical examination and laboratory and imaging tests. Among the investigated patients with LP we found: 16 cases of hepatic dysfunction (20.8%), 7 cases of renal dysfunction (9.1%), 11 cases of metabolic disorders (14.3%) and 14 cases of urinary tract infections (18.2%). No differences were found between patients with cutaneous and oral LP. The linear regression analysis revealed: positive association between concentrations of urobilinogen and bilirubin (r = 0.174, p = 0.044), negative association between albumin and creatinine (r = -0.316, p = 0.007), positive association between glucose and ketones (r = 0.266, p = 0.098) and positive association between leucocyturia and urine nitrite levels (r = 0.202, p = 0.050). Based on clinical and laboratory data, 85.7% of results obtained from urine biochemistry were confirmed. This analysis did not find any difference between patients with cutaneous and oral LP. By determining a full panel of urine metabolites through reflectometric analysis we were able to identify the main pathological changes in patients with LP.