IP Law Daily, PATENT—N.D. Ill.: Weight loss device patentee not entitled to default judgment for improper service on Chinese defendants, (Aug 6, 2026)

By Saurabh Kashyap, B.A., M.A., LL.B., LL.M.

The weight-loss device maker did not make reasonable efforts to locate the Chinese defendants’ addresses before obtaining email service barred by the Hague-Service Convention.

A federal district court in Illinois denied a medical device developer's motion for default judgment against seven Chinese online sellers accused of counterfeiting its patented weight-loss device, holding that the defendants had not been properly served. Applying the Seventh Circuit's recent decision in Kangol LLC v. Hangzhou Chuanyue Silk Imp. & Exp. Co., 177 F.4th 793 (7th Cir. 2026), the court concluded that service by email on defendants located in China violated the Hague Service Convention because the plaintiff failed to demonstrate, before seeking alternative service, that it had exercised reasonable diligence to determine the defendants' physical addresses (Erchonia Corporation LLC v. The Partnerships And Unincorporated Associations Identified On Schedule A, No. 1:25-cv-13039 (N.D. Ill. Aug. 3, 2026)).

Weight-loss patent dispute. Erchonia Corporation LLC ("Erchonia") develops medical laser technology and markets the FDA-approved Emerald Laser, a weight-loss treatment device protected by its patents. The defendants are seven entities located in the People's Republic of China that allegedly sold counterfeit versions of the Emerald Laser, marketed as the "MaxMaster Slim," through online marketplaces including Made-in-China and DHGate.

Erchonia alleged that the defendants formed an interconnected group that imported and sold infringing products into the United States. Shortly after filing suit in October 2025, it sought permission to serve the defendants by email under Federal Rule of Civil Procedure 4(f)(3), asserting that electronic service was the most reliable means of communicating with online marketplace sellers and that it could not determine their physical locations. The court granted expedited discovery and a temporary restraining order but denied a preliminary injunction. None of the defendants appeared, prompting Erchonia to seek entry of default and default judgment.

While that motion was pending, however, the Seventh Circuit decided Kangol, holding that service by email on defendants located in China is prohibited by the Hague-Service Convention where it applies. The district court therefore requested supplemental briefing on the impact of that decision before addressing Erchonia's request for default judgment.

Service of process. The court rejected Erchonia's argument that it should not reconsider the propriety of service because none of the defendants had appeared to raise a service defense. The court explained that a plaintiff seeking default judgment bears the burden of establishing effective service and personal jurisdiction before default may be entered. Citing be2 LLC v. Ivanov, 642 F.3d 555 (7th Cir. 2011), the court reiterated that a default judgment entered without personal jurisdiction is void.

Erchonia argued that the Hague-Service Convention did not apply because the defendants' addresses were unknown. Although it later submitted evidence describing internet searches using Google Maps, Bing, OpenStreetMaps, and Baidu Maps to locate the defendants, the court found those efforts untimely because they were undertaken only after the Seventh Circuit issued Kangol and after the court requested supplemental briefing.

The relevant inquiry, the court explained, is whether the plaintiff exercised reasonable diligence before seeking alternative service. Erchonia's original motion merely asserted that it was unable to determine the defendants' whereabouts without describing any meaningful investigative efforts. That unsupported assertion, the court held, fell short of the diligence required to establish that the defendants' addresses were unknown.

Article 19 argument. Erchonia alternatively argued that Article 19 of the Hague Service Convention permitted email service because Chinese law allows Chinese courts to authorize electronic service on parties located outside China. According to Erchonia, China should not be permitted to authorize email service abroad while objecting to foreign courts using the same method for defendants located within China.

The court rejected that argument. It concluded that Article 19 applies only when the destination country's internal law authorizes service from abroad through a particular method. It does not require reciprocal treatment or permit foreign courts to rely on methods that the destination country has not authorized for inbound service. Because China has objected to service through postal channels under Article 10(a), and Kangol held that the Convention excludes unenumerated methods such as email, Article 19 did not provide an alternative basis for electronic service. The court also distinguished earlier district court decisions permitting email service, explaining that they predated Kangol and rested on legal reasoning the Seventh Circuit had since rejected.

Outcome. Having concluded that Erchonia failed to establish proper service of process, the court denied its motion for entry of default and default judgment. It directed the parties to submit a status report proposing the next steps in the litigation.

The Case is No. 1:25-cv-13039.

Judge: Alexakis, G.

Attorneys: David Randolph Bennett (Direction IP Law) for Erchonia Corp. LLC.

Companies: Erchonia Corp. LLC

Cases: Patent IllinoisNews GCNNews