How Did Juliet Die?

Juliet took a drug given her by Friar Lawrence, which made her fall into a trance so her family thought she was dead and put her in the family tomb. Romeo was then supposed to come and rescue her. However he never got the message about the plan: So, thinking she was dead, he bought poison, went to the tomb and drank it. Juliet woke to find him dead, kissed him to take the poison from lips and also stabbed herself with his dagger.

She stabbed herself with a dagger after seeing what she thought was romeos dead body

In Romeo and Juliet the heroine dies twice: The first time of poison and then when she revives after her lover kill himself, she kills herself with a dagger.