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                                                                       EXHIBIT 5

                                October 17, 1996

Cardinal Health, Inc.
5555 Glendon Court
Dublin, OH  43016

Gentlemen:

                  I have acted as counsel to Cardinal Health, Inc., an Ohio
corporation (the "Company"), in connection with Post-Effective Amendment No. 1
on Form S-8 to the Company's Registration Statement on Form S-4 (the
"Registration Statement") filed under the Securities Act of 1933 (the "Act")
relating to the issuance of up to 152,880 Common Shares, without par value (the
"Common Shares"), of the Company pursuant to the PCI Services, Inc. Stock Option
Plan, as amended (the "Plan").

                  In connection with the foregoing, I have examined: (a) the
Amended and Restated Articles of Incorporation, as amended, and Restated Code of
Regulations, as amended, of the Company, (b) the Plan, and (c) such records of
the corporate proceedings of the Company and such other documents as I deemed
necessary to render this opinion.

                  Based on such examination, I am of the opinion that the Common
Shares available for issuance under the Plan, when issued, delivered and paid
for in accordance with the terms and conditions of the Plan, will be legally
issued, fully paid and nonassessable.

                  I hereby consent to the filing of this Opinion as Exhibit 5 to
the Registration Statement and the reference to me in Item 5 of Part II of the
Registration Statement.

                                       Very truly yours,

                                       /s/ Paul S. Williams
                                       Paul S. Williams, Esq.

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