A large part of the state is being warned of a high risk of epidemic thunderstorm asthma today.
The Department of Health says the main areas of concern are the Mallee, South West and Wimmera.
The combination of forecast high grass pollen levels and thunderstorms with strong winds means that there is a chance that a large number of people may develop asthma symptoms over a short period of time.
The Ballarat area is rated as a moderate risk.
You're encouraged to call Nurse on Call on 1300 60 60 24 or see your local doctor if you require medical advice.