What is the ratio in American Cyanamid v Ethicon?

Interim injunctions should be granted where there is a serious question to be tried, damages would be inadequate, and the balance of convenience favours the applicant.

What did the court decide in American Cyanamid v Ethicon?

The House of Lords granted the interim injunction and established the three-stage test that replaced the previous 'prima facie case' requirement.

Why is American Cyanamid v Ethicon important for injunctions?

It created the standard test for interim injunctions used across all civil litigation, providing clear practical guidelines for courts and practitioners.

What is the ratio in American Cyanamid v Ethicon?

Interim injunctions should be granted where there is a serious question to be tried, damages would be inadequate, and the balance of convenience favours the applicant.

What did the court decide in American Cyanamid v Ethicon?

The House of Lords granted the interim injunction and established the three-stage test that replaced the previous 'prima facie case' requirement.

Why is American Cyanamid v Ethicon important for injunctions?

It created the standard test for interim injunctions used across all civil litigation, providing clear practical guidelines for courts and practitioners.

Equity & Trusts1 min read

Injunctions — American Cyanamid Co v Ethicon Ltd

[1975] AC 396House of Lords1975

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“Interim injunctions granted where serious question, inadequate damages, and balance favours applicant.”

Facts

American Cyanamid sought interim injunction to prevent Ethicon marketing surgical sutures allegedly infringing their patent. Ethicon argued the patent was invalid.

Issues

What test should courts apply when deciding whether to grant interim injunctions pending full trial of the substantive issues.

Held

The House of Lords granted the interim injunction and established a three-stage test replacing the previous 'prima facie case' requirement.

Significance

Revolutionized interim injunction practice by creating clear, practical guidelines. Remains the fundamental test applied across all areas of civil litigation.

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OSCOLA Citation

American Cyanamid Co v Ethicon Ltd [1975] AC 396

InjunctionsCivil ProcedureIntellectual PropertyInterim Relief

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