'J'ai la grippe', 'j'ai un rhume', 'j'ai de la fièvre': articles with illnesses
In English you usually say I have flu, I have a cold or I have a fever, and the article barely matters. French almost never drops the article with an illness, and it does not use the same one every time. You say j'ai la grippe, but j'ai un rhume and j'ai de la fièvre. Each illness tends to come with its own article, so the article is part of the expression.
English speakers trip over this in two ways. They leave the article out (j'ai grippe is wrong), or they copy the English article (j'ai une fièvre sounds odd for an ordinary temperature). The good news is that the choices follow three broad tendencies, and a handful of very common expressions cover most everyday conversations.
The verb is nearly always avoir, followed by an article and the illness. The article tends to fall into one of three groups:
The classic, well-known illnesses that everyone catches in the same way, plus a few everyday states: la grippe, la varicelle, le hoquet, la gueule de bois.
Something you have as one countable case or episode: un rhume, un cancer, une pneumonie, une infection.
A symptom or condition seen as an amount, more or less of it: de la fièvre, de la toux, du diabète.
Treat these as tendencies, not strict laws. French speakers learn each expression as a fixed chunk, and some illnesses allow two versions. The safest approach is to learn the article together with the word, just as you learn its gender.
The common childhood and infectious diseases take the definite article: la grippe, la rougeole, la varicelle, la diarrhée. So do the historical or serious infectious diseases you might meet in the news or in books: la tuberculose, le choléra, la peste, la rage, la variole, la malaria. Everyday states work the same way: le hoquet, la nausée and la gueule de bois. In everyday speech you will also hear la gastro for a stomach bug.
These are illnesses you have as one case: un rhume, un cancer, une pneumonie, une infection, une allergie (often + à: une allergie aux chats). A sore throat is une angine. A single attack of migraine is usually une migraine.
Here the illness is seen as a quantity: de la fièvre, de la toux, du diabète.
J'ai la migraine is also common and simply means "I have a headache." Une toux works when you describe the cough itself: une toux sèche, a dry cough. Le vertige is mostly fear of heights, while des vertiges means dizzy spells. For diabète, people often say il est diabétique, and for rhume, je suis enrhumé.
The indefinite and partitive articles become de after pas, but the definite article stays: je n'ai pas de rhume and je n'ai pas de fièvre, but je n'ai pas la grippe.
When you talk about the illness itself rather than a patient, the definite article comes back: le cancer, le diabète. The h of hoquet is aspirated, so say le hoquet, never l'hoquet. Pain in a body part uses a different pattern, avoir mal à, which is covered in its own article.
Never drop the article with an illness, and learn each one with its usual article. Classic infectious diseases and everyday states tend to take le / la (la grippe, le hoquet). Single cases take un / une (un rhume, un cancer). Symptoms seen as an amount take du / de la (de la fièvre, de la toux).







