The price of the bitcoin fell by 10.9 percent in the night from Monday to Tuesday to below 50,000 dollars (41,072 euros).
This is due to concerns among investors that the price of the digital currency may have risen too fast.
Investors also cash in on their profits.
It is the largest drop for the world's most famous crypto coin in a month.
On Sunday, bitcoin hit a record level of more than $ 57,000, but has since started to decline.
This may also be due to a tweet from Tesla CEO Elon Musk, who wrote on Sunday that the prices of the bitcoin and the crypto currency ethereum "seem high".
Ethereum's price has also fallen sharply.
In the night from Monday to Tuesday, bitcoin was worth $ 54,911, a few hours later it was 'only' $ 49,169.
The price then briefly scrambled past the $ 50,000 mark, but dipped below it again not much later.
Microsoft co-founder Bill Gates said recently that people need to be careful not to get into some sort of mania with digital coins and that caution is advised when investing in digital currencies.
US Treasury Secretary Janet Yellen, in turn, said bitcoin is a very inefficient way to handle transactions and is a highly speculative investment.