Summary of Terms of Option Exchange

Exhibit 99(a)(1)(C)

SUMMARY OF TERMS OF OPTION EXCHANGE

RESPONSE DUE BEFORE MIDNIGHT, PACIFIC STANDARD TIME,
ON MONDAY, FEBRUARY 25, 2002, UNLESS THE OFFER IS EXTENDED

You must check your election, sign and date the Election Form and return the Election Form to Steve Hurst or Bob Harper at Inhale's corporate headquarters in San Carlos, California before midnight, Pacific Standard Time, on February 25, 2002 (or a later expiration date if the offer is extended). If you have any questions regarding the process for returning the Election Form, please contact Steve Hurst or Bob Harper via e-mail at exchange@inhale.com . Alternatively, you may reach Steve Hurst via telephone at (650) 631-3118 or Bob Harper at (650) 631-3222.

The following summarizes the principal terms and conditions of the Offer to Exchange outstanding stock options (the "Offer to Exchange," which, as it may be amended from time to time, constitutes the "Offer"). Please also read the enclosed Offer to Exchange in its entirety, because the information in this summary is not complete and does not contain all of the information relevant to your decision to participate in the Offer.

Which Options are Eligible Options and Which Options are Mandatory Exchange Options? All outstanding options to purchase shares of Common Stock (the "Common Stock") granted prior to July 24, 2001, other than Evergreen Options (as defined below), with exercise prices per share greater than or equal to $25.00 per share granted under the 2000 Non-Officer Equity Incentive Plan, as amended (the "Plan"), and held by employees of Inhale Therapeutic Systems, Inc. (the "Company" or "Inhale") or its subsidiaries (each an "Eligible Participant") are "Eligible Options." "Evergreen Options" are options to purchase Common Stock of the Company granted under the Plan to employees that vest at the rate of 1/12th per month over twelve months, beginning at the end of the vesting period of a previously-granted option.

If you wish to accept this Offer with respect to any or all of your Eligible Options, you must exchange all options to acquire Common Stock of the Company granted to you since July 24, 2001, including, without limitation, options with an exercise price of $25.00 per share or less, Evergreen Options, and options granted pursuant to plans other than the 2000 Non-Officer Equity Incentive Plan (the "Mandatory Exchange Options"). For example, if you were granted an option on May 9, 2001 with an exercise price of $31.00 per share and a second option on October 2, 2001 with an exercise price of $14.00 per share, and you elect to accept this Offer with respect to the Eligible Option granted on May 9, 2001, you must exchange all of your shares subject to the Mandatory Exchange Option granted on October 2, 2001 as well.

Who Can Participate in the Exchange? You can elect to surrender for cancellation any Eligible Options if you are an Eligible Participant on February 25, 2002. Termination of your employment with the Company or its subsidiaries on or before February 25, 2002 will automatically revoke any election that you make to participate in the Offer. Executive officers of the Company are not eligible to participate in the exchange.

How Many Replacement Options Will I Receive? The Company is conducting the exchange with respect to Eligible Options on a one-for-two (1:2) basis. Thus, for those employees who elect to participate in the Offer, on August 26, 2002 (or a later date if Inhale extends the Offer), the Company will grant you a Replacement Option covering fifty percent (50%) of the number of shares subject to your Eligible Options that were cancelled (so long as your employment or service with the Company or one of its subsidiaries continues through that date). THEREFORE, FOR EVERY TWO SHARES OF COMMON STOCK ISSUABLE UPON EXERCISE OF ELIGIBLE OPTIONS THAT YOU

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EXCHANGE, THE COMPANY WILL GRANT YOU A REPLACEMENT OPTION TO ACQUIRE ONE SHARE OF COMMON STOCK.

The Company is conducting the exchange with respect to Mandatory Exchange Options on a one-for-one (1:1) basis. Thus, for employees that elect to exchange any Eligible Options pursuant to the Offer, on August 26, 2002 (or a later date if Inhale extends the Offer), the Company will grant you a Replacement Option covering one hundred percent (100%) of the number of shares subject to your Mandatory Exchange Options that were cancelled (so long as your employment or service with the Company or one of its subsidiaries continues through that date). If you do not elect to exchange any Eligible Options, no Mandatory Exchange Options will be exchanged.

Except for the number of shares subject to the Replacement Options issued in exchange for Eligible Options and the exercise price of the Replacement Options, the terms and conditions of your Replacement Options will be substantially the same as your Eligible Options and Mandatory Exchange Options that were cancelled. The exercise price per share of the Replacement Options will be equal to the closing price of the Company's Common Stock as reported on the Nasdaq National Market on the last market trading day prior to the date of grant. The number of option shares to be represented by the Replacement Options will be adjusted for any stock splits, stock dividends, recapitalizations or similar transactions that may ...