Michael D. Nelson v. MATRIXX INITIATIVES, INC., a Delaware corporation

NOT FOR PUBLICATION
UNITED STATES COURT OF APPEALS
FOR THE NINTH CIRCUIT
MICHAEL D. NELSON,
Plaintiff - Appellant,
v.
MATRIXX INITIATIVES, INC., a
Delaware corporation and ZICAM, LLC,
an Arizona limited liability company,
Defendants - Appellees.
No. 12-17455
D.C. No. 3:09-cv-02904-WHA
MEMORANDUM*
Appeal from the United States District Court
for the Northern District of California
William Alsup, District Judge, Presiding
Submitted January 16, 2015 **
San Francisco California
Before: WALLACE, M. SMITH, and FRIEDLAND, Circuit Judges.
Michael Nelson appeals from the district court’s orders excluding Nelson’s
two expert witnesses on specific causation, and granting Matrixx’s motion for
FILED
FEB 02 2015
MOLLY C. DWYER, CLERK
U.S. COURT OF APPEALS
* This disposition is not appropriate for publication and is not precedent
except as provided by 9th Cir. R. 36-3.
** The panel unanimously concludes this case is suitable for decision
without oral argument. See Fed. R. App. P. 34(a)(2).

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summary judgment. Because the parties are familiar with the facts and procedural
history of this case, we repeat only those facts necessary to resolve the issues
raised on appeal. We affirm.
In a toxic tort case in California, a plaintiff must show both general
causation, which is “that the substance at issue was capable of causing the injury
alleged,” and specific causation, which is “that the substance caused, or was a
substantial factor in causing, the specific plaintiff’s injury.” Avila v. Willits Envtl.
Remediation Trust, 633 F.3d 828, 836 (9th Cir. 2011) (citing Jones v. Ortho
Pharm. Corp., 209 Cal. Rptr. 456, 462 (Cal. Ct. App. 1985)). General and specific
causation “must be proven within a reasonable medical probability based upon
competent expert testimony.” Jones, 209 Cal. Rptr. at 460.
Nelson offered Drs. Davis and Hwang as experts on the issue of specific
causation, and both Drs. Davis and Hwang relied on differential diagnosis for their
expert opinions that Nelson’s smell loss was caused by Zicam. “Differential
diagnosis is a common scientific technique, and federal courts, generally speaking,
have recognized that a properly conducted differential diagnosis is admissible
under Daubert.” Clausen v. M/V New Carissa, 339 F.3d 1049, 1057 (9th Cir.
2003). However, “expert testimony that neglects to consider a hypothesis that
might explain the clinical findings under consideration may also be unreliable.” Id.
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at 1058. Elimination of the potential causes “must be founded on more than
‘subjective beliefs or unsupported speculation.’” Id. (quoting Claar v. Burlington
N. R.R. Co., 29 F.3d 499, 502 (9th Cir. 1994)).
The district court excluded Dr. Davis’s testimony and expert report, and Dr.
Hwang’s testimony, because it found that neither expert was able to provide a
reliable method for ruling in Zicam, or ruling out age or the cold virus as the cause
of Nelson’s smell loss. As the district court states, “[b]oth age and the cold virus
are well-established, common causes of smell loss.” The district court did not
abuse its discretion in concluding that Nelson’s two expert witnesses were not
sufficiently reliable on the issue of specific causation, and in excluding both
experts on that basis.
After excluding Drs. Davis and Hwang, the court granted Matrixx’s motion
for summary judgment because Nelson had provided no additional expert
testimony on the issue of specific causation and therefore could not prove a
necessary element in his case. Without any reliable expert witness testimony on
specific causation, the district court correctly granted Matrixx’s motion for
summary judgment.
Finally, because none of Nelson’s remaining arguments find support in
either the facts or law, the district court correctly declined to shift the burden of
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proving causation to Matrixx, correctly precluded reliance on FDA action or
discovery of third party medical histories, and correctly rejected Nelson’s claim to
recover the purchase price of Zicam.
AFFIRMED.
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