Coffee spots are persistent hyperpigmented spots with different sizes and clear borders, not related to sunlight. Café-au-lait spots are light brown spots, ranging from a few millimeters in diameter to round oval or irregular spots with a diameter of ten to twenty centimeters. The disease can be treated by pulsed laser, but the efficacy is unpredictable, some patients can be cured, but some patients relapse soon after healing, and some patients are ineffective even after applying pulsed laser treatment of various wavelengths for unknown reasons. Generally speaking, the darker the color, the better the effect, and the lighter the color, the worse the effect. With the current technology, the commonly used lasers are emerald laser, ruby laser, Nd:YAG laser, dye laser, and multifrequency 532 laser. However, with the current science and technology, there is no laser that can achieve completely ideal results, and relatively speaking, the effect of the emerald laser is better than other lasers. But no matter how good the treatment is, the effect is not really related to the number of treatments, generally one or two treatments are enough, no matter if you have good or bad results, one or two treatments are enough. The effect will not be significantly different because you treat more times, the real effect is good, just one or two, the effect is not good, even if you then treat a ten times, there is not much obvious difference. Although some people are treated many times, but the number of times the treatment, more because of the actual operation of different doctors and different levels of experience and ability, not necessarily to the number of times to see the effect of treatment, not to say that the more times the treatment is better, after all, the more times, the more money you spend.