WASHINGTON (AP) — On Monday, President Donald Trump signed an order. It says drug companies must make their medicines cheaper in the U.S. in 30 days. If they don't, the government will pay less for the medicines later.

The person in charge of health, Robert F. Kennedy Jr., has one month to agree on new prices for medicines. If they don't agree, Kennedy has to create a new plan. This plan will make the US pay the same low prices for medicines as other countries.

On Monday, Trump said everyone would pay the same amount, like people in Europe.

It's not clear how the president's order will affect many Americans who have their own health insurance. The government can change the price of medicine for people with Medicare and Medicaid.

After the Republican House shared its plan to save a lot of money from Medicaid, Trump also talked about saving money on medicine prices.

Drug companies in the US did not like Trump's rule. They said it was not good for patients. Drug companies say that if they make less money, they cannot research and make new medicines.

Stephen J. Ubl, the head of PhRMA, said that bringing in drug prices from other countries would not be good for people in America. He said it would mean fewer new medicines and would put at risk the large amount of money their companies plan to spend in America.

Trump wanted the U.S. to pay less for some medicines, like other countries do. People have argued about this idea since he first tried it. Near the end of his time as president, he signed a paper saying the U.S. should only pay less for certain medicines given at a doctor's office, like shots or cancer treatments given by drip.

This small rule had problems because a court stopped it. This happened when President Biden was in charge. Companies that make medicine said that when President Trump tried to do this in 2020, it would help other countries decide how much medicines should cost in America.

During a speech at the White House on Monday, Trump defended drug companies and said other countries were responsible for the high cost of medicine in America. He was joined by several people, including Kennedy and Dr. Mehmet Oz.

But he said he would investigate the companies and let the U.S. buy more medicine from other countries.

Trump said that drug companies make most of their money from America. He also said that is not good.

Trump spoke a lot about the news on the weekend. He said his plan could save a lot of money, saying 'TRILLIONS OF DOLLARS.'

But on Monday, the White House did not say how much money they thought they could save.

Important people from the health department will meet with leaders of drug companies next month. They will offer new prices for drugs. These prices will be based on what other countries pay, Oz said on Monday.

Rachel Sachs, an expert on health laws, said Americans probably won't see lower prices for medicine soon because of the order.

Sachs said, "It looks like the plan is to ask companies to make their products cheaper on their own, but we don't know how much. If they don't make prices low enough, the government will do other things. But it will take a very long time, maybe years, to make medicine cheaper in the future."

The government health department can change the prices of some medicines in certain programs, but its power is not complete. A new law now lets Medicare talk about prices for a few medicines starting in 2026. Before this law, Medicare paid the prices that the medicine companies asked for. Medicine companies tried to stop the law, but they did not win.

It is harder for the agency to change the price of medicine for many Americans who have private insurance.

The U.S. usually pays more for medicines than other rich countries. Both big political parties are often angry about this, but they haven't found a solution in Congress.

When Trump became president, he said that companies making medicine were doing bad things and charging too much. He also said that other countries were taking advantage of Americans because they paid less for medicine.

Before the announcement, Trump wrote angry words about drug companies online. He said that for many years, drug companies told people that only Americans paid for their research.

He said that money from drug companies for politicians "can help a lot, but not with me or my party."

We will do what is right, he said.

Some companies that make medicine had a good day on the stock market on Monday morning. For example, the price of shares for the company Merck went up. The companies Pfizer and Gilead Sciences also saw their share prices go up.