Charak Samhita is a classical Ayurvedic text that provides a comprehensive understanding of the human body, health, and disease. It is divided into two main parts: Purvardha and Uttarardha. Here are four features of Charak Samhita Purvardha:

1. Fundamental principles: The Purvardha lays down the fundamental principles of Ayurveda, such as the theory of Panchamahabhuta (the five elements), the concept of Doshas (vital energies), and the theory of Agni (digestive fire). It provides a detailed explanation of how these principles govern the human body, mind, and spirit.

2. Diagnosis: The text provides a detailed description of the process of diagnosis in Ayurveda.

3. Treatment methods: Charak Samhita Purvardha discusses various treatment methods, including medicinal herbs, diet, lifestyle modifications, and cleansing procedures. It emphasizes the importance of individualized treatment plans based on the patient's constitution, the specific nature of the disease, and the stage of the disease.

4. Disease prevention: The text provides guidelines for disease prevention, emphasizing the importance of a healthy lifestyle, proper diet, and exercise. It also discusses the importance of seasonal and environmental factors in maintaining optimal health and provides guidelines on how to manage these factors.