In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Bilateral haemorrhagic infarction of the globus pallidus after cocaine and alcohol intoxication .
### Output Text:
Bilateral haemorrhagic infarction of the globus pallidus after <span class="chemical">cocaine</span> and <span class="chemical">alcohol</span> intoxication . 