You don't need a medical certificate to go through the US Customs. We just need to bring our ID cards and passports.
Precautions for going through the US Customs:
First, to enter the US Customs, you must fill in two forms, one is the US Customs Declaration Form and the other is the US Entry-Exit Certificate (I-94). American customs officials will check these two forms and finally decide whether you can enter the United States and how long you can stay in the United States. Please take care of it and carry the I-94 form with you at all times, especially when you leave the United States temporarily, otherwise you will not be able to return again.
Second, you must declare the excess cash you bring to the United States. When entering the United States, according to the regulations of CBP of the Customs Border Protection Bureau, if you bring more than 1, yuan in cash and fail to declare it truthfully, the customs will confiscate it according to law.
the state administrative organ that exercises the functions and powers of import and export supervision and administration according to the laws and administrative regulations of the country (or region). The word "Customs" in English originally refers to a kind of local tax paid by merchants on the way to trafficking goods, which has the nature of "road money" or "passage fee" and "use fee" for ports and markets. After the cancellation of this local tax, the word "Customs" refers to the import and export tax levied by the government. the Customs is the government agency that collects import and export taxes, that is, the customs, which is a state organ that supervises, checks and collects tariffs on all goods and articles entering and leaving the country.