===Knowledge of disease===
After thorough examination of an individual, one shall evaluate the disease. The second part of diagnostic protocol provides comprehensive knowledge of disease. This includes the methods to elucidate causative factors[[hetu]], observe premonitory signs and symptoms[[purvarupa]], clinical features[[rupa]], pathogenesis [[samprapti]], and pacifying factors [[upashaya]]. The set of these five diagnostic tools is called as 'Nidana Panchaka'. This is described and applied in clinical practice to know each disequilibrium condition.
The phenomena of a disease causing another disease is described as [[Nidanarthakara roga]]. [[Upadrava]] (complications), [[Udarka]] (marks of disease after it is cured) are applied for knowing the cause-effect relationship in pathogenesis of disease.