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: For the first few days after ingestion , she was in a confused state and had mild to moderate ataxia and giddiness .
### Output Text:
For the first few days after ingestion , she was in a confused state and had mild to moderate ataxia and giddiness . 