The utilization of machine learning and image processing for illness detection is covered in this chapter. The importance of disease detection, the function of machine learning in the identification of diseases, the various machine learning methodologies for identifying illnesses, and the various data sources that are employed are all covered, in addition to the numerous applications of machine learning and image processing. Medical images, including radiology images and histopathology images, are amid the images used for disease detection. This chapter offers a concise outline of the literature on image processing and machine learning for the recognition of plant or crop and human diseases by reviewing several research studies in related fields. Even though there has been a lot of research on this subject, some of it has been covered in the literature review. This chapter is organized into multiple separate sections, the main points of which are discussed in the conclusion and discussion sections, following which further research is suggested for future investigation.