Hello Yolibolli, thank you for your question. The glass containers are very heat-resistant and can be used in the oven, as the glass can withstand temperatures of up to 250 degrees. However, to prevent the glass from becoming brittle and breaking, you should be careful not to cause a thermal shock. Thermal shock occurs when the glass is exposed to a temperature difference of more than 42°C. You should therefore limit temperature fluctuations by preheating the oven while the jars are already in it. Kind regards, Angela