It sounds like you're concerned about the side effects of a medicine that caused your mother-in-law to vomit.

When a medicine causes vomiting, it is often due to its side effects, which can vary depending on the specific drug. Common side effects that might lead to vomiting include:

• Gastrointestinal irritation: Many medications can upset the stomach lining, causing nausea and vomiting.
• Allergic reactions: Sometimes, the body reacts adversely to a drug, leading to symptoms like vomiting.
• Overdose or sensitivity: Taking too much or being sensitive to a medication can cause vomiting.

To provide accurate information, it would be helpful to know the exact medicine your mother-in-law took. Meanwhile, if vomiting is severe, persistent, or accompanied by other symptoms like abdominal pain, dizziness, or rash, it is important to seek medical attention promptly.

If you can share the name of the medicine, I can offer more specific information about its side effects and what steps to take next. In any case, consulting a doctor, preferably a specialist such as a pharmacist or the prescribing physician, is recommended to ensure safe management.