2000
Behavioural effects were tested using a context dependent conditioned emotional response test ( CER ) which showed that animals treated with 5 - FU had a significant reduction in freezing time compared to controls .
 Chemical: 5 - FU
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: 5 - FU