What kind of disease is the lack of strength in both feet? There are several possible diseases: First, the patient may have Greenbrier syndrome. Greenbrier syndrome starts with weakness of both limbs, especially the lower limbs on both sides, and the feeling of unstable walking. Second, we should pay attention to whether there is myelitis, acute myelitis will appear lower limb weakness, as well as sensory disorders, urinary and fecal disorders. Third, we should pay attention to the presence of vascular diseases of the spinal cord, which can also cause weakness of both feet. Fourth, there are some diseases such as lumbar disc herniation and diabetic peripheral neuropathy. There are also intracranial diseases, such as bilateral anterior cerebral artery infarction, which can also cause weakness in both feet.