You can look at the tongue color, tongue shape, tongue coating, etc. to assist in determining the heat and cold, but Chinese medicine generally need to be four diagnostic reference, not only through the tongue to determine the heat and cold.
1. Look at the tongue color: patients with cold symptoms usually have a lighter tongue color than normal. Patients with heat syndrome usually have a darker tongue color than normal, which is bright red.
2. Look at the shape of the tongue: patients with cold syndrome usually have a fat, tender and pale tongue with obvious teeth marks. Patients with heat syndrome usually have a swollen tongue with a deep red color.
3. Look at the tongue coating: patients with cold syndrome usually have white coating. Patients with heat syndrome usually have yellow moss.
It should be noted that the consumption of certain foods (such as chocolate) can color the tongue, and clinical attention should be paid to exclude artifacts caused by such reasons.
Consultation with a doctor is recommended for specialized medical questions.