Exhibit 99.1

                SONUS PHARMACEUTICALS RECEIVES FDA ACTION LETTER


BOTHELL, Washington, March 14, 2000--SONUS Pharmaceuticals, Inc. (Nasdaq:SNUS)
announced today receipt of an action letter from the U.S. Food and Drug
Administration (FDA) that extended the approvable status of EchoGen(R)
(perflenapent injectable emulsion), the Company's first ultrasound contrast
agent. SONUS had received an approvable letter for EchoGen in April 1999
indicating that the product could be approved once certain conditions are
satisfied, and the Company submitted a response to the approvable letter in
September 1999. In the new action letter received by SONUS, the FDA is
requesting a reanalysis of certain data that may affect product labeling.

 "We are surprised by the FDA's request because we felt that we had addressed
all of the FDA's concerns in our September 1999 submission and in subsequent
conversations with agency reviewers. Our next step is to meet with the FDA to
clarify the requests of the action letter and to discuss how we can best respond
and the timeframe for our response. Our objective remains to move as quickly as
possible to secure final approval of EchoGen," said Michael A. Martino, SONUS
President and CEO.

The Company's application to the FDA is for the use of EchoGen in the
echocardiographic evaluation of left ventricular endocardial border delineation
and left ventricular chamber opacification. Echocardiography is a diagnostic
ultrasound test of the heart used to identify abnormal cardiac function and
structure. EchoGen has been administered to more than 2,200 patients and
volunteers in worldwide clinical studies, including some studies of severely ill
patients with congestive heart failure and chronic obstructive pulmonary
disease. The side effects of EchoGen observed in clinical trials were mostly
mild and transient and most occurred within 30 minutes of administration. The
most frequent adverse reactions associated with the use of EchoGen are
vasodilation/flushing (3.1%), headache (1.8%), and taste perversion (1.3%).

The European Commission issued marketing authorization for EchoGen in the 15
countries of the European Union in 1998 for use in patients with suspected or
established cardiovascular disease. In Europe, EchoGen is approved for use in
patients who have had previous inconclusive non-contrast studies to provide
opacification of cardiac chambers and enhance left ventricular border
delineation with resulting improvement in wall motion visualization. In 1999,
SONUS received approval of manufacturing variations to the European marketing
license which are required to launch EchoGen in Europe.

EchoGen is a fluorocarbon-based liquid emulsion that is changed into gas
microbubbles upon syringe activation prior to injection into the bloodstream of
a patient. EchoGen is highly reflective of ultrasound signals which enables
clinicians to more clearly identify the border between the blood and the
surrounding tissue being imaged. Better ultrasound images can give physicians
more diagnostic information, potentially helping them make more accurate and
confident diagnoses.

SONUS Pharmaceuticals, Inc., located in Bothell, Washington, is engaged in the
research and development of proprietary ultrasound contrast agents and drug
delivery systems for use in the diagnosis and treatment of heart disease, cancer
and other debilitating conditions.

Contacts: Gregory Sessler or Pamela Dull, SONUS Pharmaceuticals, Inc., (425)
487-9500.

The Company's news releases and other corporate information are available on
SONUS' web site at www.sonuspharma.com. News releases may also be obtained via
fax by calling 800-758-5804, Ext. 108377.

Certain of the statements made in this news release are forward-looking such as
those, among others, relating to the regulatory review process for EchoGen and
benefits of ultrasound contrast agents. As discussed in the Company's annual
report on Form 10-K filed February 29, 2000, actual results could differ
materially from those projected in the forward-looking statements as a result of
the following factors, among others: there can be no assurance that SONUS can
meet the requirements of the FDA action letter, or any subsequent conditions, in
a timely manner if at all, or that EchoGen will ultimately receive regulatory
approval; market acceptance of the Company's products will depend upon a number
of factors, including safety, efficacy, ease of administration, the presence of
competitive imaging products or technologies and the availability of
reimbursement by third party payors.