A firm is said to be in a healthy state if it is able to generate positive cash flows i.e. revenues > expenses. A more specific term is Free Cash Flows (FCF) which indicates the available cash with the company after incurring all the necessary expenses.
FCF= EBIT(1-Tax Rate) + Depreciation & Amortization - Change in Net Working Capital – Capital Expenditure
FCF denoted the available amount with the firm which can be given out to the shareholders and hence indicates the health of a company. It is the FCF which an investor usually looks at while analyzing a firm.