The subject of the study is a dried drop of human oral fluid (facies). The goal is to propose a method for quantitative characteristic for the crystalline structure of oral fluid using fractal theory. The task is to create a computer program to calculate the fractal dimension, the area of crystals; length and width of the axes of mixed human saliva crystals. Methodology. To create a computer program for quantitative description of the crystalline structure of the oral fluid facies. The program was created within the framework of cooperation between Omsk State Medical University and Omsk State Technical University. The program, called FracSquare, was developed using the Python programming language version 3.1 and the built-in libraries math, cv2 and plt, which implement algorithms for finding the Minkowski fractal dimension, searching and counting pixels located inside the desired object, as well as an algorithm for finding the hypotenuse. After installing on the computer and launching the program, you need to load a photo of the saliva facies and calculate the fractal dimension and crystal area by pressing the appropriate buttons; the result will appear on the screen in the form of numerical values. Results. The computer program FracSquare allows you to mathematically calculate the fractal dimension, the area of crystals, and also measure the length and width of the branches of human saliva crystals. These digital values provide a quantitative characterization of the crystalline pattern of the saliva facies. Conclusion. The operator receives accurate digital values using a developed computer program, on its basis he can objectively evaluate the microcrystalline pattern of the facies of human saliva in order to identify pathological processes occurring in the body. The indicator of these processes is oral fluid.