<em><strong>Objective</strong><em> To determine erythrocyte response against the All In One Light multipurpose solution used for cleaning contact lenses. <em><strong>Methodology</strong><em> 5 mL of each of the following substances were placed in test tubes: distilled water, All In One Light solution, 0.9% NaCl solution and 6% NaCl solution then, three drops of sheep blood were added to each solution, left to rest for twenty minutes, and observations were made on the optical microscope at 100 X. The solutions were then centrifuged at 1500 rpm for 10 minutes, and the effect in color of the supernatant and presence or absence of precipitate was observed. <em><strong>Results</strong><em> The surface morphology of the erythrocytes in the All In One Light and 0.9% NaCl solutions had a smooth appearance, with 6% NaCl was perforated and cell debris was revealed with distilled water. The supernatants color after centrifugation in the All In One Light solution and the distilled water was deep red and in the 0.9% NaCl solution and 6% NaCl solution it was light red. <em><strong>Conclusions</strong><em> The All In One Light solution is isotonic compared to the blood plasma, despite the partial hemolysis.