Vertical lines on the middle fingernail may be due to inflammation, toxin issues, excessive fatigue, or trauma.

1. Potential Inflammation or Toxin Issues

In daily life, if vertical stripes appear on the fingernails and are black, it is important to be vigilant. This often indicates that there may be chronic inflammation in the body, or even a large amount of toxins have accumulated in the body. It could also be a sign of excessive liver fire. For these issues, it is recommended to reduce liver heat and consume more detoxifying foods. Drinking plenty of water and exercising regularly can also help expel toxins from the body. Over time, you may find that the vertical stripes on your nails gradually disappear.

2. Potential Association with Excessive Fatigue

If you have been in a state of excessive fatigue for a period of time, such as engaging in heavy physical labor or sustained mental workload, it can lead to poor rest and unbalanced diet. When combined with high stress levels, vertical stripes may appear on the nails. These stripes are related to the body's condition. In such cases, it is important to adjust your emotions, get more rest, and maintain a balanced diet. Over time, you may notice that the vertical stripes on your nails gradually fade away.

3. Potential Trauma Issues

In daily life, if the nails accidentally sustain external pressure or injury, it can leave marks on the nails. These marks are the result of external trauma and will gradually disappear over time. There is no need to worry excessively about this. If your nails appear smooth, shiny, and rosy, vertical stripes on them are likely unrelated to your health and may be due to genetic factors.